I find hums totally bogus, I have no idea how loud the hum in the room is when I am humming.
I was reading the BULLRUN documents and came across the description of HONKER which was an iPhone/Android app with a backdoor that could be activated and cause an MP3 to be played if the GPS said the phone was in a particular location. I didn't immediately get the purpose of this scheme until reading Dave's post. Then I woke up and I was in the admin plenary.